Plate clamping mechanism for printing machines



W. F. HUCK Jan. 27, 1942.

PLATE CLAMPING MECHANISM FOR PRINTING MACHINES Filed May 19, 1939 INVENTOR Mll am FHucK. BY

Patented Jan, 2 1942 PLATE CLAMPING IMECHANISM FOR v PRINTING MACHINES William F. Huck, Richmondjlill, N. Y., assignon to R. Hoe

ration of New York & Co., Inc., NevVYork, N. Y.,'a col-p Application May 19, H339, Serial No. 274,509

(Cl. 101 4l5.1)

14 Claims.

This invention relates to clamps for securing printing plates to the form cylinders of printing machines, and more. specifically to an arrangement including a plate clamping support, for holding the plate clamps in the cylinder at a plurality of positions, to accommodate plates having difi'erent dimensions.

The form of plate clamp and support shown herein is especially adapted to lithographic, intaglio and other machines of the class which print from relatively thin plates that are held on the cylinder under tension, by clamps engaging the leading and trailing edges of the plate.

In lithographic printing especially, it is sometimes necessary to use plates of different lengths, but'this cannot be done on presses as heretofore constructed, and it therefore has beennecessary for a printing plant tohave a printing machine for each size of plate that it is desired to use.

In order to provide a printing machine that is adapted to receive more than one size of plate and thereby reduce the number of printing machines Figure l is a broken top plan view of an improved plate cylinder with the improved plate clamping means of this invention shown in operative position thereon; a

Figure 2 is an end view of the parts shown in Figure 1, looking in. the direction of arrows 22 of Figure 1 and with the parts arranged to clamp a plate of one length on the cylinder; and

Figure 3 is an enlarged portion of an end view similar to Figure 2 but with the parts arranged to clamp a considerably shorter plate on the cylinder.

The improved plate cylinder ll of this invention, as shown in the drawing, is adapted to have thin metallic plates l2 stretched tightly over its periphery and secured thereto by an improved plate clamping mechanism. The clamping mechanism is of such structure that a plate II, of a length sufl'lcient to extend about the periphery of the cylinder II from A to B, (see Figure 2) may be secured to thecylinder, and by the simple expedient of removing the plate clamping mecharequired in a printing establishment to handle a certain range of work, as hereinafter disclosed, there is now provided a plate cylinder and a plate clamping mechanism therefor, having certain of its members movable into different positions to thereby adapt them to this requirement. An object of the invention is to provide in a plate cylinder, means including a removable plate clamp holding segment, and a plate clamping mechanism, whereby either of two lengths of plates may be accommodated.

Another object is to provide in a plate cylinder for a printing machine adapted to print from relatively thin plates a reversible segment part arranged to receive and hold a removable plate clamping mechanism which includes a plate clamping bar adjustably secured to the segment part and having plate clamping jaws adapted to engage a relatively thin plate.

It is also an object of this invention to provide a lithographic plate cylinder of generally improved construction, whereby the device will be simple, durable and inexpensive in construction. as well as convenient, practical, serviceable and efficient in its use. With the foregoing and other objects in view, which will appear as the description proceeds, the invention resides in the combination and arrangement of parts, and in the details of construction hereinafterrdescribed and claimed.

The preferred embodiment of the invention is illustrated in the accompanying drawing, wherein:

nism in a segment part l3, which is set into the cylinder I l at its periphery, reversing thesegment part l3 in the cylinder II, and then replacing the clamping mechanism, a plate of a length sufficient to extend about the cylinder from A to C may then be clamped on the cylinder.

The segment part l3 (see Figure 1) extends lengthwise of the cylinder II from one end to the other and is secured thereto by a plurality of spaced apart screws l4 and I5, which extend through the segment part l3 and-screw thread into threaded openings 5 and I1 respectively, provided in the cylinder II, when the segment part I3 is in the position shown in Figures 1 and 2. When the segment part I3 is removed from the cylinder H, and reversed into the position shown in Figure 3, the respective screws l4 and i5 screw thread into threaded openings l8 and I9 respec tively, provided in the cylinder Il'. Y

The segmentpart I3 is provided with a recess 2|, which extends lengthwise thereof its entire length. The recess 2| is disposed in the part 13 considerably off-center and is of suflicient width to receive a plate clamping bar 22 carrying a plurality of clamping lugs 23, and-to permit adjusting them peripherally about the cylinder H, and is of suflicient depth to dispose them entirely within the dimensions of the cylinder.

The plate clamping bar 22 extends substantially the entire length of the segment part l3 and is secured to the segment part H! by a plurality of spaced apart screws 24, which extend through elongated openings 25 in the bar 22 and are screw threaded into threaded openings 26 in the segment part l3. The threaded openings 28 are disposed substantially midway between the side walls 21 and 28 01' the'recess 2|. The openings 25 are elongated circumferentially oi the cylinder to permit adjustment of the bar 22 peripherally about the cylinder within the recess 2|, the elongated openings 25 being wider than the diameter of the screws 24 to permit slight misalignment of the bar 22 in the recess 2| whenthis is desired.

Along the front side 29 of the bar 22, a raised plate engaging jaw 3| is formed over which an edge 32 of the plate I2 is disposed to be clamped thereagainst by jaws 33 of the clamping lugs 23, which are forced downwardly to clamp the plate edge 32 against the jaw 3|, by spaced apart screws 34 and 35, the lugs 23 being fulcrumed along their rear edges 36 upon a raised rib 31 provided along the rear side edge 38 of the bar 22 for this purpose. Coiled springs 39 react against the lugs 23 to raise them out of clamping engagement with the plate edge, when the screws 34 and 35 are loosened.

Spaced apart screws 4| screw threaded into the bar 22 and extending therefrom at both sides, have their threaded ends 42 shouldered to press against a hardened metal block 43 and force it againstthe side wall 28 of the recess 2| (as seen inTFigure 3), and thereby stretch a. plate |2 held between the jaws 33 and the raised jaw 3| on the bar 22. In the construction shown, the block 43 is secured to the threaded end 42 of each screw 4| by riveting it into a counterbore 44 I in the block 43.

The other edge 45 of the plate l2, (see Figure 2), is secured to the cylinder II by a conventional form of clamp mechanism disposed in a recess 46, provided to receive it. This clamp mechanism includes a block 41 to which the plate edge 45 is clamped by a clamp plate 48 secured by screws 49.

When it is desired to secure a shorter plate to the cylinder I, such as one having a length that it would extend about the cylinder from A to C, the bar 22 with its associated clamp lugs 23 is removed from the segment part I3 by removing the screws 24. The segment part I3 is then removed from the cylinder H by removing the screws l4 and I5, and is then reversed, and the screws 4 and I are screwed into the openings I8 and I9 respectively. The bar 22 with its assOciated clamp lugs 23 is then replaced and se cured in the recess 2| by means of the screws 24, with the hardened metal blocks 43 abutting the side wall 28 of the recess 2|, as shown in Figure 3.

From the above description, it is obvious that provision has been made in a plate cylinder structure, whereby the cylinder may be arranged to accommodate plates of different lengths in an expeditious and eiilcient manner.

It will be seen that the bar 22 is reversible with respect to the segment part l3 and that the latter is reversible with respect to the cylinder, but that in changing from one length of plate to another length for which the mechanism is 4| provide for movement 01' the clamp bar 22 to the extent necessary to hold plates that vary tributes thereof, and it is therefore desired that the present embodiment be considered in all re spects as illustrative and not restrictive, and it will be further understood that each and every novel feature and combination present in or possessed by the mechanism herein disclosed forms a part of the invention included in this application.

What I claim is:

1. In a plate cylinder for a printing machine adapted to print from relatively thin printing plates, a movable and reversible segment part having an ofl-center recess, set into the cylinder at its periphery, and a plate edge clamping and stretching mechanism removably secured to the segment part within the recess, and reversible with respect thereto.

2. In a plate cylinder, means to clamp plates of different lengths about and upon the periphery 01' the cylinder including means to clamp a first edge of either a long or a short printing plate to the cylinder, and a removable and reversible segment having means to clamp a second edgeof a relatively short plate to the cylinder when the segment is secured to the cylinder in one manner and to clamp a second edge of a longer plate to the cylinder when the segment is reversed.

3. In a plate cylinder, means to clamp printing an ofi-center recess, set into the periphery oi and removably secured to the cylinder and extending lengthwise thereof substantially the entire length of the cylinder, a plate clamping bar removably and adjustably secured to the segment plate, and a plate clamping jaw secured on the plate clamping bar.

5. In a plate cylinderhaving means to clamp plates 01' diflerent lengths about and upon its periphery, means to clamp one edge of a plate to the cylinder, a reversible segment plate set into the periphery of and removably secured to the cylinder, the segment plate having an oilcenter seat and extending lengthwise of and substantially the entire length of the cylinder, a plate clamping member removably and adjustably secured to the seat of the segment plate, a plate clamping jaw secured on the plate clamping member, and means to adjust the plate clamping member with the plate clamping jaw thereon in respect to the segment plate to stretch a plate extending peripherally about the cylinder between them and the plate clamping means.

6. In a plate cylinder, a segment part having an off-center recess therein set into the periphcry of the cylinder and adapted to be reversed in position therein, means to secure the said part to the cylinder in either position, a plate clamping device mounted in the recess in the segment part and adapted to be reversed in position therein, and means to adjust the said device relatively to the said part and circumferentially with respect to the cylinder to tighten a plate about the cylinder.

'7. In a plate cylinder for a printing machine, the said cylinder having a recess, a first plate clamp mechanism adapted to engage one edge of a printing plate, a plate clamp carrier within the said recess, having an arcuate surface corresponding to the periphery of the cylinder and an off-center slot, and a second plate clamp mechanism secured within the slot and adjustable with respect to the carrier to clamp a plate.

8. In a plate cylinder for a printing machine, a first plate clamp mechanism adapted to engage one edge of a printing plate, a reversible cured in the recess in the segment plate and including an adjusting means in engagement with one of the shoulders of the segment plate and being reversible therein to cause the adjusting means to engage the opposite shoulder.

12. In a plate cylinder for a printing machine, a first means adapted to clamp one edge of a relatively thin printing plate on the cylinder, a second means adapted to engage and clamp the opposite edge of the plate on the cylinder, the said second means being removably secured to a reversible member fastened to the cylinder and having an off-center recess arranged to receive the second means, the said second means being arranged to engage and clamp the edge of a plate of one length extending peripherally about the cylinder when the member is fastened to plate clamp carrier having an arcuate plate sup- I porting surface and an off-center slot, and a second plate clamp mechanism secured within the slot and adjustable with respect to the carrier to clamp a plate.

9. In a printing machine, in combination, a plate cylinder adapted to have a thin plate wrapped thereabout, a plate edge clamp secured to the cylinder, the cylinder having an axially;

'wrapped' thereabout, a plate edge clamp secured to the cylinder, the cylinder having an axially extending recess formed in its peripheral surface and circumferentially spaced from the plate edge clamp, a segment plate removablysecured in the recess in the cylinder and being reversi ble therein circumferentially of the cylinder, the segment plate having a recess formed in its outer surface, extending circumferentially of the cylinder and terminating nearer to one edge of the segment plate than to the other edge, and a second plate edge clamp removably secured in the recess in the segment plate and being reversible therein to face either edge of the segment plate.

11. In a printing machine. in combination. a plate cylinder adapted to have a thin plate wrapped thereabout, a plate edge clamp secured to the cylinder, the cylinder having an axially extending recess formed in its peri heral surface and circumferentially s aced from the plate edge clamp to form opposin sho lders. a se m nt plate removablv secured in the recess in the cylinder with its edges abutting-the shoulders and being reversible therein to abut opposite edges with opposite shoulders, the segment plate having an off-center recess therein extending the length thereof to-form opposing shoulders,

and a second plate edge clamp removably se-- the cylinder in one position, and the edge of the plate of a different length when the member is fastened to the cylinder in a reversed position.

13. In a printing machine cylinder having a peripheral surface adapted to receive a printing plate formed of sheet material, a first plate clamping means at one edge of the plate receiving surface and adapted to clamp one edge of a printing plate, a recess in the cylinder at the opposite edge of the plate receiving surface, a segment member having an arcuate surface conforming to the periphery of the cylinder, a second plate clamping means adapted to be supported adjacent the arcuate surface of the segment member and arranged to engage the opposite edge of the printing plate, and means to secure the segment member and the second clamping means in the recess in one operative relationship, with the clamping means between the arcuate surface of the segment member and the plate receiving surface, to clamp a relatively short plate on the cylinder, and alternatively, to secure the segment member and the second clamping means in another operative relationship, with the arcuate surface of the segment member between the clamping means and the plate receiving surface, to clamp a relatively long plate on the cylinder.

14. In a plate cylinder for a printing machine adapted to print from plates formed of sheet material, a continuous plate receiving surface having an area at least equal to the printing area of a printing plate, a first clamping device adapted to clamp one edge of the printing plate on the cylinder, a recess in the cylinder adjacent the opposite edge of the plate thereon, a segment member adapted to be secured in the recess and having an arcuate surface corresponding to the periphery of the cylinder, means to secure the segment member in a first position in the recess with its arcuate surface adjacent the edge of the plate receiving surface and effectively extending the area thereof, and alternatively, to secure the segment member in a second position in the recess with its arcuate surface spaced from the plate receiving surface,'a second plate clamping device adapted to draw the plate tight on the cylinder, and means adapted to secure I 

